In coupling barges together for transport, or in mooring barges, it has been standard practice to attach a wire cable to the barges to be connected, following which a ratchet or winch is employed to take up slack to tighten the cable between the barges. This leaves no provision for the barges to rise and fall individually in the water, thereby causing the cable to break, due to tremendous stress and strain thereon. This, in turn, results in runaway barges which create a serious hazard to other marine vehicles, human life and stationary structures such as bridges. Similar problems exist in the coupling and docking of other types of marine vehicles.